Abstract

We have investigated photoluminescence properties of ZnO and thin films at grown on a ZnOcrystal substrate by pulsed laser deposition. The structural characterization with x-ray diffraction and atomic force microscopy demonstrates the pseudomorphic growth of the thin film and the atomically smooth surface. It has been found that a photoluminescence band originating from the transition of in the thin film appears in the energy region of deep-level transitions in a ZnO crystal: The photoluminescence-decay time is in the order of sub-milliseconds. The photoluminescence-excitation spectrum of the Mn-related transition exhibits a peaky structure with a broad profile at the energy lower than the -exciton energy by . This indicates that the light incorporation of Mn to ZnO leads to a negative energy shift of the band-gap energy. The broad profile of the band-edge transition observed in the photoluminescence-excitation spectrum suggests that the incorporation of Mn produces remarkable random-potential fluctuations.